Adds <cms:layout> tag that generalizes previous grid template additions.
Fixes ClassCastException when ContainerSection.getChildren references an orphaned object.
Changes SEO and URL widgets to show up if the object is an instance of a subclass of Page.
Fixes NPE when section type info is lost in admin/templates page.
Changes LayoutTag to use the new HtmlGrid object from Dari.
Changes Page.getAreas to return a map instead of a list.
Removes PageFilter.Static.getSection and replaces it with the sections request attribute.
Deprecated Page.Layout.